A Potentiometric and (31P,51V) NMR Study of the Aqueous Molybdovanadophosphate System

Selling, Anna; Andersson, Ida; Grate, John H.; Pettersson, Lage

doi:10.1002/1099-0682(200007)2000:7<1509::aid-ejic1509>3.0.co;2-7

Cited by 36 publications

(30 citation statements)

References 23 publications

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“…S4, a typical spectrum of HPA‐5 is given, revealing that a solution of HPA‐5 always contains the whole series of HPA‐ n from n = 1 to 5 and phosphoric acid, which is a residue from the synthesis. The number of peaks in the spectrum for every HPA‐ n corresponds with the number of isomers that is for HPA‐1 (H 4 [PVMo 11 O 40 ]) only 1, for HPA‐2 (H 5 [PV 2 Mo 10 O 40 ]) 5, for HPA‐3 (H 6 [PV 3 Mo 9 O 40 ]) 13, and for HPA‐4 (H 7 [PV 4 Mo 8 O 40 ]) 27 isomers .…”

Section: Resultsmentioning

confidence: 99%

Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5

et al. 2020

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The triphasic aerobic extractive desulfurization of benzothiophene (BT) using an aqueous H8[PV5Mo7O40] solution as catalyst and O2 as oxidant was investigated. A time‐resolved analysis of all reaction products in the gas, organic and aqueous phase, is given. The organic sulfur in BT is mainly converted to sulfuric acid. Mass transport limitations can be excluded. The reaction orders are 1 with regard to BT, and 0.5 both for HPA‐5 and O2. Calculated data derived from this mechanism with a power law kinetic approach show good agreement to the experimental data for conversions below 60 %. At higher BT conversions, significant deviations are found, suggesting that acidic products formed in the BT oxidation affect the catalyst and therefore the initial kinetics of the BT oxidation.

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Section: Resultsmentioning

confidence: 99%

Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5

et al. 2020

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“…The observed overlapping complicates precise determining the content of V V O 2 + ions and individual HP‐anions in modified solutions. All resonances with x ≥ 2 on 31 P spectra contain ‘fine structure’ that is a consequence of existing positional isomerism ,. The prepared HPA solutions can be represented as a mixture of different Keggin HP‐anions, where the excess of V V is present as VO 2 + cations associated with these anions and H z PO 4 (3–z)– .…”

Section: Resultsmentioning

confidence: 99%

Multicycle Testing of P‐Mo–V Heteropoly Acid Catalysts in Oxidation of Substituted Phenols

2018

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A series of valuable para‐quinones, such as 2,3‐ and 2,6‐dimethyl‐1,4‐benzoquinones (Me2BQs), were synthesized via oxidation of the corresponding 2,3‐ and 2,6‐dimethylphenols by using homogeneous high‐vanadium solutions of heteropoly acids: H11P3Mo18V8’O87 (HPA‐8’) and H17P3Mo16V10’O89 (HPA‐10’). These catalysts were shown to be capable of interdependent and reversible change of their acid and oxidative properties, the efficient regeneration of which can be performed for 25 min. The complete optimization of reaction conditions allowed one to reach the selectivity of the desired Me2BQs in 95–97% and shorten the oxidation time. The structural integrity of heteropoly anions present in the catalyst solutions was found to persist during the repeated performing substrate oxidation and catalyst regeneration. The catalysts showed the preservation of stability and efficiency for 25 cycles, demonstrating the prospectivity of high‐vanadium heteropoly acids in oxidation of organic substances.

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“…The Keggin‐type Mo‐V‐P HPA‐ x aqueous solutions are complex equilibrium mixtures, containing HP‐anions [H x –1 PV V x Mo 12– x O 40 ] 4− with integer x values as well as H + and VO 2 + cations . The partially reduced HPA‐ x solutions also contain VO 2+ cations and various mixed valence HP‐anions [H x + m –1 PV IV m V V x – m Mo 12– x O 40 ] 4− = HPAn m with integer x and m values (0 ≤ m ≤ x ).…”

Section: Resultsmentioning

confidence: 99%

Regeneration of the Oxidation Catalysts Based on the Aqueous Solutions of Non‐Keggin Mo‐V‐P Heteropoly Acids by Molecular Oxygen

Жижина

Odyakov

2014

Int J of Chemical Kinetics

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Kinetic peculiarities of regeneration of the aqueous solutions of non‐Keggin‐type Mo‐V‐P heteropoly acids HaPzMoyVx′Ob (HPA‐x′) and their acidic salts by O2 are studied. The HPA‐x′ solutions have heightened thermal stability that permits to consider them as highly efficient catalysts for different oxidation processes. In the HPA‐x′ and their salts solutions, these peculiarities prove to be similar. The studied reaction is of the first order with respect to O2 and V(IV), if [V(IV)] is higher than 0.8 M. As [V(IV)] decreases during the reaction, its order with respect to V(IV) increases to the third. The apparent activation energy of the reaction at temperatures 150–170°С is 37.5 kJ mol−1. The obtained kinetic equation was used to calculate a new effective air reactor for the regeneration of the homogeneous HPA‐x′ catalyst in a pilot process of methylethylketone synthesis.

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A Potentiometric and (31P,51V) NMR Study of the Aqueous Molybdovanadophosphate System

Cited by 36 publications

References 23 publications

Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5

Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5

Multicycle Testing of P‐Mo–V Heteropoly Acid Catalysts in Oxidation of Substituted Phenols

Regeneration of the Oxidation Catalysts Based on the Aqueous Solutions of Non‐Keggin Mo‐V‐P Heteropoly Acids by Molecular Oxygen

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